1. Field of the Invention
The present invention relates to a method for managing a defective area on a high density optical disc, and more particularly to a write once optical disc, an apparatus and a method for managing a defective area on a high density optical disc such as a Blu-ray Disc Write Once (BD-WO).
2. Background of the Related Art
Optical discs on which a large capacity of data can be written as optical recording media have widely been used. Among them, a new HD-DVD (High-Density Digital Versatile Disc) on which video data and audio data can be written and stored in high quality and in large quantities, e.g., a BD (Blu-ray Disc), has been recently developed.
The Blu-ray disc, which belongs to the next-generation HD-DVD technology, is the next-generation optical recording solution that can strikingly surpass the data recording capability of existing DVDs. The Blu-ray disc world standards of HD-DVD that have recently been established include the use of a celadon laser having a wavelength of 405 nm that is much denser than a red laser of existing DVD technology having a wavelength of 650 nm. Accordingly, a greater amount of data than the existing DVD technology can be stored on the BD that has a thickness of 1.2 mm, a diameter of 12 cm, and an optical transmission layer having a thickness of 0.1 mm.
As various kinds of standards related to the BD (Blu-ray Disc) are being developed, various kinds of standards for BD-RE (BD Rewritable disc) and BD-WO (BD Write Once disc) are being developed. One of the new high density optical discs, on which high quality video and audio data can be written, erased and rewritten for long periods of time, is a Blu-ray Disc Re-writable (BD-RE) that is currently being developed.
FIG. 1 schematically illustrates the structure of a recording area of a BD-RE. The BD-RE of FIG. 1 shows the structure of the recording area of a disc having one recording layer. Seen from the inner periphery of the disc, the recording area is divided into a lead-in area, a data area, and a lead-out area. An inner spare area ISAO and an outer spare area OSAO for replacement of a defective area are provided on the inner and outer peripheries of the data area, and a user data area for recording user data is provided in the center of the data area.
If a defective area exists in a user data area during recording of data on a BD-RE, the data recorded in the defective area is shifted to and recorded in a spare area as replacement data. Also, position information relating to the defective area and the replacement data recording area is recorded in defect management areas DMA 1, DMA 2, DMA 3 and DMA 4 provided in the lead-in and lead-out areas. The position information serves as management information for the defective area to perform defect management for the optical disc. In the case of the BD-RE, since rewriting is possible in any area of the disc, the whole area of the disc can randomly be used irrespective of its recording mode.
The Blu-ray Disc Write-Once (BD-WO) is another type of high density optical disc that is being developed where a high quality of data can be recorded and reproduced to and from the disc. As the name may suggest, data can be written only once on the BD-WO and is not re-writable on the BD-WO. However, the BD-WO can be read repeatedly. As a result, the BD-WO is useful where the rewritability of data on a recording medium is not desired or essential.
Discussions on the standardization of high density optical discs, e.g., such as BD-WO, have recently been underway. In this regard, a disc structure, a method and an apparatus for managing defective areas of the BD-WO are needed, which accommodate and consider the unique characteristics and intended operations of the BD-WO. Such techniques will render the BD-WO commercially marketable and operationally feasible.
In the BD-WO (Blu-ray Disc Write Once), since only a single recording of data in a specified area of the disc is possible, the recording mode is greatly restricted. Accordingly, it is difficult to randomly use the whole area of the disc due to its management difficulty. Also, in a high-density optical disc of write once type, such as the BD-WO, the management of the defective area becomes an important aspect of data recording. Accordingly, the optical disc of write once type requires a unified standard of management for defect information on optical discs of this type.